The Air Force’s Top Secret Space Plane is Launching Again This Weekend

A mysterious military space plane that has operated largely in secret over the past decade is scheduled to launch on its sixth voyage on Saturday, according to the U.S. Air Force.

The X-37B Orbital Test Vehicle, which looks like a miniature version of NASA’s Space Shuttle, was built by Boeing and is owned by the Air Force, though this mission will be operated by the newly formed Space Force. It is currently slated to lift off from Cape Canaveral Air Force Station on a United Launch Alliance Atlas V rocket between 8:24 and 10:53 AM EDT on May 16.

While most of the military research planned for this mission is secret, as is usually the case for the plane, the X-37B will carry unclassified experiments from NASA, the Naval Research Laboratory (NRL), and the Air Force Academy.

"This sixth mission is a big step for the X-37B program," said Randy Walden, director and program executive officer for the department of the Air Force Rapid Capabilities Office, in a statement.

"This will be the first X-37B mission to use a service module to host experiments,” he noted. “The incorporation of a service module on this mission enables us to continue to expand the capabilities of the spacecraft and host more experiments than any of the previous missions."

Perhaps the most exciting experiment is a prototype solar panel, developed by NRL, which represents the first orbital test of a dazzlingly futuristic idea: space-based solar power. This decades-old concept envisions a massive solar power plant in space that collects sunlight and converts it into microwave energy that can be beamed down to Earth.

The dream is to establish an off-Earth power grid that could meet the entire world’s energy needs with renewable and clean solar power from space. But there are still countless technical challenges that stand in the way of this lofty goal, and it could take decades, or longer, to develop such advanced space-based power infrastructure.

That said, every revolutionary technology starts with modest prototypes like the NRL’s solar panel, which will test out the process of converting sunlight into microwave beams in an orbital environment.

“This is a major step forward,” Paul Jaffe, an electronics engineer at the Naval Research Lab and lead researcher on the project, told Daniel Oberhaus at WIRED. “This is the first time that any component geared towards a solar-powered satellite system has ever been tested in orbit.”

In addition to the NRL prototype, the X-37B will carry two NASA experiments into orbit that will examine the effects of the space environment on seeds and material samples. The plane will also deploy a small satellite built by Air Force Academy cadets, called FalconSAT-8, into orbit.

Presumably, the X-37B will be getting up to all sorts of other secret stuff as well, but it could be many years–if ever—before we find out about its classified activities.